McGraw Hill Asu: Pehmeäkantinen kirja Painos: 2. painos Julkaisuvuosi: 2004, 16.12.2002 (lisätietoa) Kieli: Englanti
A number grid is a matrix which consists of rows of boxes, ten to each row, containing a set of consecutive whole numbers. Children use number grids to explore number patterns, reinforce place-value concepts, and calculate sums and differences.